Cisco Cisco Email Security Appliance C170 Guia Do Utilizador
13-16
Cisco AsyncOS 9.1 for Email User Guide
Chapter 13 Anti-Spam
Determining Sender IP Address In Deployments with Incoming Relays
Figure 13-4
Mail Relayed by MX/MTA — Simple
shows two other, slightly more complicated examples of how mail may be relayed inside the
network and how mail may be processed by several servers within the network before it is passed to the
Cisco appliance. In example A, mail from 7.8.9.1 passes through the firewall and is processed by an MX
and an MTA before being delivered to the Cisco appliance. In example B, mail from 7.8.9.1 is sent to a
load balancer or other type of traffic shaping appliance and is sent to any one of a range of MXs prior to
being delivered to the Cisco appliance.
Cisco appliance. In example A, mail from 7.8.9.1 passes through the firewall and is processed by an MX
and an MTA before being delivered to the Cisco appliance. In example B, mail from 7.8.9.1 is sent to a
load balancer or other type of traffic shaping appliance and is sent to any one of a range of MXs prior to
being delivered to the Cisco appliance.
Figure 13-5
Mail Relayed by MX/MTA — Advanced
Cisco IronPort Email Security appliance
Firewall
MX / MTA
Sending
Machine
Machine
IP: 7.8.9.1
IP: 10.2.3.4
IP: 10.2.3.5
Cisco IronPort Email Security appliance
Firewall
MX
Sending
Machine
Machine
IP: 7.8.9.1
IP: 10.2.3.4
IP: 10.2.3.6
MTA
IP: 10.2.3.5
Hop 2
Hop 2
Hop 1
MX
IP: 10.2.5.1-n
MX
IP: 10.2.6.1
Mail Filter
Hop 1
A
B